Support assemblies for mineral mines

ABSTRACT

A support assembly with two frames each having telescopic props carried by base members pivotably interconnected to a rigid member disposed therebetween. The rigid members are connected through a shifting device usable to alternately advance the frames. Each frame has a leaf spring attached at its center to the rigid member and pivotably connected at its ends to the base members or props. Between the center and each end of the spring is a portion which follows a sinusoidal course. Upon pivotal movement of a base member and the rigid member in one direction the associated portion of the spring elongates and eventually limits the amount of pivotal movement. Pivotal movement in the opposite direction is limited when the portion of the spring engages an abutment surface of the rigid member.

United States Patent Beulker et al.

[ SUPPORT ASSEMBLIES FOR MINERAL MINES [72] inventors: Franz Beulker, Langern; Erich l-ioiimann,

Altlunen, both of Germany [73] Assignee: Gewerkschaft Eisenhutte Westfalia,

Wethmar near Lunen, Westfalia, Germany 22 Filed: Mar. 24, 1970 [21] Appl. No.: 22,318

[451 Mar. 28, 1972 Primary Examiner-Dennis L. Taylor Attorney-Sughrue, Rothwell, Mion, Zinn & Macpeak 57 ABSTRACT A support assembly with two frames each having telescopic props carried by base members pivotably interconnected to a rigid member disposed therebetween. The rigid members are connected through a shifting device usable to alternately advance the frames. Each frame has a leaf spring attached at its center to the rigid member and pivotably connected at its ends to the base members or props. Between the center and each end of the spring is a portion which follows a sinusoidal course. Upon pivotal movement of a base member and the rigid member in one direction the associated portion of the spring elongates and eventually limits the amount of pivotal movement. Pivotal movement in the opposite direction is limited when the portion of the spring engages an abutment surface of the rigid member.

PATENTEDMAR28 m2 FEGQ.

SUPPORT ASSEMBLIES FOR MINERAL MINES BACKGROUND OF THE INVENTION Movable support assemblies for mineral mines are known which are basically composed of two alternately shiftable frames each with telescopic props capable of being braced between the floor and roof of a mine working.

To enable such a frame to adapt itself as far as possible to any uneveness in the floor of a mine working and to maintain the props as far as possible in an upright position it is customary for the props to be resiliently interconnected at the base and this arrangement has generally proved satisfactory. Nevertheless the arrangement does suffer from the drawback that no appreciable prop supporting forces can be imparted to the floor by the connection and thus the prop supporting forces are concentrated at the base of the props or at the sole plates of the props. The danger therefore arises, particularly in the case of a soft floor and/or very high prop supporting forces, that the bases of the props or the aforesaid sole plates will be pressed into the floor thus impeding shifting of the frame.

Arrangements are also known in which the props of a frame are connected at their bases by a rigid cross piece articulated to the props. In this case likewise, the frame is able to adapt itself to a certain extent to unevenness in the floor and this arrangement provides the advantage that the prop supporting forces can be introduced into the floor not only by means of the bases of the props but at the same time by means of the rigid cross piece so that the frame is adequately supported by a substantial area of floor supporting surface with consequential moderate pressure per unit area. A major drawback of this arrangement, however, is that owing to the articulated interconnection between the cross piece and the props, when the load is removed and the frame shifted the props can assume an inclined position relative to the floor and may even perform oscillations. The action of shifting the frame and correctly positioning the props after shifting will in this case involve difficulties.

The object of this invention is to overcome these disadvantages.

A further object of the invention is to provide an assembly wherein the props are maintained in an upright position and frames will adapt themselves to unevenness in the floor of a mine working.

Another object is to ensure that the prop supporting forces can be transmitted over a relatively great area to the floor.

SUMMARY OF THE INVENTION According to the present invention there is provided a movable support assembly including a frame, said frame havmg:

a. two base members each with a floor-engaging surface;

b. a telescopic prop received by each base member;

c. a rigid member pivotably attached to each base member and having a floor-engaging surface; and

d. a leaf spring attached to the rigid member and adapted to exert a force which biases the props into an upright position in relation to said floor engaging surfaces and to limit the relative pivotal movement of the base members and the rigid member.

Further according to the invention there is provided a movable support assembly composed of two frames interconnected by means of a shifting device; each frame having two telescopic props received by base members, the base members of each frame being interconnected by means of a rigid member pivotably attached to said base members and a leaf spring attached to the rigid member and adapted to limit the relative pivotal movement of the base members and the rigid member and to bias the props into a substantially upright portion relative to the floor-engaging surface of the frame. The rigid member preferably has a lateral opening receiving U- shaped springs attached to the rigid member and to the associated shifting device. If desired the props can be welded to the base members.

According to a further feature of the invention the leaf spring can have a central portion affixed to the rigid member while its ends are connected to the base members or directly to the props. The leaf spring can be secured to an upper face of the rigid member by means of a removable securing plate.

According to a further feature of the invention, the leaf spring has two portions each formed to follow an undulatory course. Preferably these portions are located between the central portion and the ends of the spring and the portions preferably follow a sinusoidal course. In this case the assembly can with advantage be so designed that each of the portions of the leaf spring can be elongated to a maximum extent upon pivotal movement between an associated one of the base members and the rigid member in one direction, said maximum extent being reached when the pivotal angle between the rigid member and the base member is not greater than 15.

In a preferred constructional version the connections between the leaf spring and the base members are situated vertically above the associated pivotal connections between the rigid member and the base members. The rigid member preferably has oblique surfaces each formed between a zone at which the rigid member is connected to the leaf spring and one of the base members. Each oblique surface can be disposed in proximity to one of said two portions of the leaf spring and contacts said one portion which then forms a stop surface upon pivotal movement between an associated one of said base members and the rigid member in 'the other direction. I

The assembly made in accordance with this invention enables articulation to take place between the base members, or the props, and the rigid member, in opposition to the restoring force of the leaf spring, so that the base members and the rigid member can adapt themselves to the uneven places in the floor and the frame will at the same time rest on the floor over a substantial area thereby retaining adequate rigidity.

The movement due to the pivotal connections on the other hand, is restricted by the limits defined by the leaf spring and excessive movements and consequential undesirable inclination of the props are avoided.

The invention may be understood more readily and various other features of the invention may become more apparent from consideration of the following description.

BRIEF DESCRIPTION OF DRAWINGS A constructional embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawing, wherein:

FIG. 1 is a part sectional plan view of the base part of a support assembly made in accordance with the invention;

FIG. 2 is a side view of the base shown in FIG. 1, the support view being partly in section; and

FIG. 3 is a cross sectional view taken along the line IIIIII of FIG. 1.

DESCRIPTION OF PREFERRED EMBODIMENT As shown in FIG. 1, a mine roof support assembly is composed of two parallel support frames A and B interconnected by means of a guiding and shifting device C. Each frame A, B can be shifted alternately by means of the device C in known manner and in accordance with the progress of the mining operation. Each frame A, B is provided with two hydraulic telescopic props, denoted D in FIG. 2 which engage base members 1 and 2 which are in turn connected together by a rigid connecting member 3. To this end, the base members 1, 2 have recesses 30 into which the bottoms of the props are received. The bottoms of the props can be welded into the members 1, 2 or else as in this embodiment, the props can just rest in the recesses 30. As shown each member 1, 2 is constructed in two separate parts la lb and 2a 2b respectively, and these parts la lb or 2a 2b are detachably interconnected by means of bolts 5 and can be separated along vertical planes 4. The edge 10 of the part lb of each frame is disposed at the front end of the frame, i.e., in the direction in which the frames A B are shifted, is formed as a skid, as can be seen more particularly in FIG. 2.

As shown in FIG. 3 each member 3 is a rigid I-shaped casting connected with the two base members 1, 2 via pivotal joints 6, 7. The axes of the joints 6, 7 are situated at a slight distance above the lowermost supporting surfaces 11 of the frames engaged on the floor of the mine working.

The maximum vertical height of the member 3 is somewhat smaller than the maximum height of the base members 1, 2 and the member 3 tapers from its central portion towards the joints 6, 7 and thus the oblique abutment surfaces 12 are produced on its upper face. The member 3 is formed with apertured lugs at its ends and the parts la 2a of the base members 1, 2 are formed with upper and lower correspondingly apertured shackles 9. The lugs 10 are each received between two of the lowermost shackles 9 and a pivot pin 8 extends through aligned apertures in the lug 10 and shackles 9.

The two base members 1, 2 of each frame A, B are also interconnected by means of a leaf spring 13 which has a central portion which is clamped to the upper face of the member 3 by means of a securing plate 15 and fixing bolts 14. The two ends of the leaf spring 13 are each bent inwards to form a loop 1311 which receives a horizontal pin 16 extending through the uppermost shackles 9 of the associated part 1a, 2a. By this arrangement each end of the spring 13 is pivotably secured to the members 1, 2 of the associated frame A, B but in a tractionally rigid manner. Moreover as can be seen in FIG. 1 the connections between each leaf spring 13 and the member 1, 2 are situated vertically above the joints 6, 7.

Where, for example, the props D are welded to the base members 1, 2 it may be desirable for the ends ofthe leaf spring 13 to be pivotably attached directly to the props D rather than to the members 1, 2. In this case the props D can have securing rings to which the spring 13 is attached.

Each leaf spring 13 has two portions 13a 13b which are situated between its articulatedly connected ends and its central portion and portion 13a 13b each follows a sinusoidal course. When the members 1, 2 and 3 are in a normal position as illustrated these portions 13a 13b are situated at a slight distance above the oblique surface 12 of the member 3.

The shifting device C is composed of a double-acting piston and cylinder unit with a cylinder 21 and a piston rod 23 extending from both ends of the cylinder 21. A rail 22 is attached to the rod 23 by means of clamping elements 24. The member 3 of each frame A, B is connected to the shifting device C by means of V-shaped springs 18. More particularly, as shown in FIG. 3 the innermost lateral opening 17 of each member 3 receives the looped part 32 of each spring 18 and the central web 31 of the member 3 is attached to the looped parts 32 of the springs 18 by means of bolts 19 extending through apertures in the web 31. The ends of each spring 18 remote from its looped part 32 thereof are also bent into eyes for receiving bolts 20 attaching the spring 18 to the device C. The spring 18 connected to the member 3 of the frame A are secured to the cylinder 21 of the device C whereas the springs 18 connected to the member 3 of the frame B are secured to the rail 22 in turn attached to the piston rod 23.

It may be seen, in particular from FIG. 2, that when the base members 1, 2 of one frame A, B are pivoted about the joints 6, 7 and in the direction shown by the arrow P relative to the member 3, the two portions 13a 13b of the leaf spring 13 tend to straighten and undergo increasing elongation. The maximum permissible elongation of the portions 13a 13b of the leaf spring 13 is reached, for example, at a relative pivoting angle of about 15 where the portions 13a 13b become substantially straight. The joints 6, 7 between the base members 1 and 2 and the member 3 therefore become effectively locked by the portions 13a 13b of the leaf spring 13 when these are in the fully elongated state and no further pivoting movement between these members can take place. When a pivoting movement takes place in the direction opposite to that shown by the arrow P, the portions of the leaf spring 17 are subjected to a pressure and eventually the portion 13a can contact the oblique surfaces 12 of the member 3, thus preventing any further pivoting movement in this direction.

When one of the props D of one of the support frames A, B is relieved of its load, the portions 13a 13b of the leaf spring 13 which are extended to a greater or smaller extent tend to exert a biasing or restoring force on the members 1 and 2 and this force causes the prop in question to return to a perpendicular position relative to the floor.

We claim:

1. A movable supporting assembly comprising:

a. two base members each with a floor-engaging surface;

b. a telescopic prop received by each ofsaid base members;

c. a rigid member pivotably attached to each base member and having a floor-engaging surface, and

d. a leaf spring attached to the rigid member and adapted to exert a force which biases the props into an upright position in relation to said floor-engaging surfaces and to limit the relative pivotal movement of the base members and the rigid member, the leaf spring having a central portion attached to said rigid member and two further portions, each said further portion being formed to follow an undulatory course, each of said two further portions being capable of elongation to a maximum extent upon pivotal movement between an associated one of the base members and the rigid member by an angle not exceeding 15.

2. In a movable supporting assembly with two'base members each with a floor-engaging surface, a telescopic prop received by each of said base members and a rigid member pivotably attached to each base member and having a floor-engaging surface; the improvement comprising a leaf spring having a central portion attached to said rigid member and two further portions which follow an undulatory course and are attached to said base members, the spring serving to exert a force which biases the props into an upright position in relation to' said floor-engaging surfaces, the further portions each being capable of elongation to a maximum extent to limit the relative pivotal movement between the associated base member and prop and the rigid member.

3. An assembly according to claim 2, wherein the connections between the base members and the leaf spring are each situated vertically above the pivotal connection between the rigid member and the associated base member.

4. An assembly according to claim 1, wherein the ends of the further portions of the leaf spring are attached to the base members.

5. An assembly according to claim 1, wherein the ends of the further portions of the leaf spring are attached to the props received by the base members.

6. An assembly according to claim 1, wherein the rigid member has oblique surfaces each formed between a zone at which the central portion of the leaf spring is connected to the rigid member and one of the base members.

7. An assembly according to claim 6, wherein each oblique surface is disposed in proximity to one of said two further portions of the leaf spring to contact said one portion and form a stop surface therefor upon pivotal movement between the associated base member and the rigid member.

8. An assembly according to claim 2, wherein the rigid member has oblique surfaces each formed between a zone at which the rigid member iscQnnected to the central portion of the leaf spring and one of the base members, each oblique surface being disposed in proximity to one of said two further portions of the leaf spring to contact said one portion and portions each of undulatory formation, the leaf spring serving to bias the props into an upright position in relation to said floor-engaging surfaces and the further portions of the leaf spring being capable of elongation to a certain extent to limit the degree of pivotal movement between an associated one of the base members and the rigid member. 

1. A movable supporting assembly comprising: a. two base members each with a floor-engaging surface; b. a telescopic prop received by each of said base members; c. a rigid member pivotably attached to each base member and having a floor-engaging surface, and d. a leaf spring attached to the rigid member and adapted to exert a force which biases the props into an upright position in relation to said floor-engaging surfaces and to limit the relative pivotal movement of the base members and the rigid member, the leaf spring having a central portion attached to said rigid member and two further portions, each said further portion being formed to follow an undulatory course, each of said two further portions being capable of elongation to a maximum extent upon pivotal movement between an associated one of the base members and the rigid member by an angle not exceeding 15*.
 2. In a movable supporting assembly with two base members each with a floor-engaging surface, a telescopic prop received by each of said base members and a rigid member pivotably attached to each base member and having a floor-engaging surface; the improvement comprising a leaf spring having a central portion attached to said rigid member and two further portions which follow an undulatory course and are attached to said base members, the spring serving to exert a force which biases the props into an upright position in relation to said floor-engaging surfaces, the further portions each being capable of elongation to a maXimum extent to limit the relative pivotal movement between the associated base member and prop and the rigid member.
 3. An assembly according to claim 2, wherein the connections between the base members and the leaf spring are each situated vertically above the pivotal connection between the rigid member and the associated base member.
 4. An assembly according to claim 1, wherein the ends of the further portions of the leaf spring are attached to the base members.
 5. An assembly according to claim 1, wherein the ends of the further portions of the leaf spring are attached to the props received by the base members.
 6. An assembly according to claim 1, wherein the rigid member has oblique surfaces each formed between a zone at which the central portion of the leaf spring is connected to the rigid member and one of the base members.
 7. An assembly according to claim 6, wherein each oblique surface is disposed in proximity to one of said two further portions of the leaf spring to contact said one portion and form a stop surface therefor upon pivotal movement between the associated base member and the rigid member.
 8. An assembly according to claim 2, wherein the rigid member has oblique surfaces each formed between a zone at which the rigid member is connected to the central portion of the leaf spring and one of the base members, each oblique surface being disposed in proximity to one of said two further portions of the leaf spring to contact said one portion and form a stop surface upon pivotal movement between the associated base member and prop and the rigid member.
 9. An assembly according to claim 1, wherein the central portion of the leaf spring is secured to an upper part of the rigid member by means of a removable securing plate.
 10. An assembly according to claim 1, wherein the props are welded to the base members.
 11. A movable support assembly comprising two frames, a shifting device connected between said frames, each frame having two base members each with a floor-engaging surface, a telescopic prop received by each of said base members, a rigid member pivotably attached to each of said base members and having a floor-engaging surface, and a leaf spring with a central portion attached to said rigid member and two further portions each of undulatory formation, the leaf spring serving to bias the props into an upright position in relation to said floor-engaging surfaces and the further portions of the leaf spring being capable of elongation to a certain extent to limit the degree of pivotal movement between an associated one of the base members and the rigid member. 